I’m I right in thinking they are a brand new set?If so, John C has your answer.
If they are second hand and leaking,then they have to be considered at being on the road to the scrap yard sooner rather than later.It may not be an issue though if you were happy at what you paid for them and if the tractor is just a hobbie horse or sees only low hours every year pottering about a farm.
In my opinion,second hand undercarriage parts,particularly chains/rails,need to be regarded as slave parts only and purchased at a cheap price that reflects that.
To do the job right,assuming you’ve actually bought second hand chains,Shimmy has your answer,but the costs to do that here in the UK are simply not feasible.We seem to live in a throw away society these days.